1. Technical Field
The present invention relates to a display device and a method of controlling a light source.
2. Related Art
In display devices, there has been known a technology of intermittently lighting (hereinafter referred to as “intermittent illumination” in some cases) a light source to thereby display an image. For example, by inserting a black screen in one frame, it is possible to reduce the afterimage felt by the user to thereby achieve improvement of the animation performance (see, e.g., JP-A-2004-302254 (Document 1), JP-A-2004-354717 (Document 2)). Further, it has been known that in the display device adopting an active-shutter system to thereby perform 3D display, in the case of switching, for example, from the display image for the right eye to the display image for the left eye, the crosstalk between the right eye and the left eye can effectively be prevented by performing black display using the intermittent illumination.
Further, the intermittent illumination is also used for the purpose of regulating the luminance (dimming the light) by controlling the lighting time per unit time besides the purpose of inserting the black screen in the frame as described above. Such dimming control is known as pulse width modulation (PWM) dimming.
In the display device, in the case of adopting the intermittent illumination for the two purposes (e.g., the insertion of a black image and the dimming control), a control section for controlling drive of the display device combines two drive signals corresponding respectively to the purposes with each other to generate a new drive signal (hereinafter referred to as a “composite drive signal” in some cases), and controls the light source using the composite drive signal. The combination of the new drive signal is performed by, for example, a logical AND operation of the two drive signals.
In this case, in order to change (e.g., the luminance) one of the two drive signals, it is necessary to also change the composite drive signal in accordance with the drive signal thus changed. It can be realized by, for example, a control section having the correspondence relationship between the one drive signal and the composite drive signal as a look-up table (LUT), and performing the control with the LUT. However, in this case, a plurality of LUT is necessary, and there is a problem that a circuit load is increased, and at the same time, the time for changing the setting is also increased.